diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index d0f858829..980e959f2 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -753,6 +753,7 @@ issues.due_date_added = "added the due date %s %s"
 issues.due_date_modified = "modified the due date to %s from %s %s"
 issues.due_date_remove = "removed the due date %s %s"
 issues.due_date_overdue = "Overdue"
+issues.due_date_invalid = "The due date is invalid or out of range. Please use the format yyyy-mm-dd."
 
 pulls.desc = Enable merge requests and code reviews.
 pulls.new = New Pull Request
diff --git a/templates/repo/issue/view_content/sidebar.tmpl b/templates/repo/issue/view_content/sidebar.tmpl
index a3f56aa29..14d88700d 100644
--- a/templates/repo/issue/view_content/sidebar.tmpl
+++ b/templates/repo/issue/view_content/sidebar.tmpl
@@ -214,7 +214,7 @@
 		<div class="ui form" id="deadline-loader">
 			<div class="ui negative message" id="deadline-err-invalid-date" style="display: none;">
 				<i class="close icon"></i>
-				The due date is invalid or out of range. Please use yyyy-mm-dd.
+			{{.i18n.Tr "repo.issues.due_date_invalid"}}
 			</div>
 		{{if gt .Issue.DeadlineUnix 0}}
 			<p>